linux/drivers/video
Noralf Trønnes ba0263340a fbdev: fb_defio: Export fb_deferred_io_mmap
Export fb_deferred_io_mmap so drivers can change vma->vm_page_prot.
When the framebuffer memory is allocated using dma_alloc_writecombine()
instead of vmalloc(), I get cache syncing problems on ARM.
This solves it:

static int drm_fbdev_cma_deferred_io_mmap(struct fb_info *info,
					  struct vm_area_struct *vma)
{
	fb_deferred_io_mmap(info, vma);
	vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);

	return 0;
}

Could this have been done in the core?
Drivers that don't set (struct fb_ops *)->fb_mmap, gets a call to
fb_pgprotect() at the end of the default fb_mmap implementation
(drivers/video/fbdev/core/fbmem.c). This is an architecture specific
function that on many platforms uses pgprot_writecombine(), but not on
all. And looking at some of the fb_mmap implementations, some of them
sets vm_page_prot to nocache for instance, so I think the safest bet is
to do this in the driver and not in the fbdev core. And we can't call
fb_pgprotect() from fb_deferred_io_mmap() either because we don't have
access to the file pointer that powerpc needs.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1461856717-6476-5-git-send-email-noralf@tronnes.org
2016-05-02 16:24:49 +02:00
..
backlight backlight: pwm_bl: Free PWM requested by legacy API on error path 2016-01-11 10:45:24 +00:00
console fbcon: set a default value to blink interval 2016-02-26 13:19:55 +02:00
fbdev fbdev: fb_defio: Export fb_deferred_io_mmap 2016-05-02 16:24:49 +02:00
logo video/logo: prevent use of logos after they have been freed 2014-12-29 10:06:55 +02:00
display_timing.c
hdmi.c [media] hdmi: rename HDMI_AUDIO_CODING_TYPE_EXT_STREAM to _EXT_CT 2015-01-27 10:19:12 -02:00
Kconfig drm: Remove two-level menu in Kconfig 2015-08-07 19:06:37 +02:00
Makefile
of_display_timing.c video: of: fix memory leak 2015-10-07 14:13:59 +03:00
of_videomode.c video: Fix possible leak in of_get_videomode() 2015-08-10 15:11:12 +03:00
vgastate.c fbdev: vgastate: remove trailing whitespaces 2015-01-13 12:53:25 +02:00
videomode.c